Census Shows Population Is Significantly Smaller Than Earlier Estimates

YANGON, Myanmar—A lower-than-expected population count is taking some of the shine off Myanmar, compelling current and hopeful investors to reassess what profits they can expect out of the frontier market.

An official census released Saturday found the population of the country was 51.4 million—significantly lower than the 60 million estimates that the Myanmar government has touted in recent years, as it started emerging from decades of economic isolation. The larger figures have been cited by companies hoping to tap the country's...